Relief lithographic plates and photosensitizing solutions

ABSTRACT

A PHOTOSENSITIZING SOLUTION HAVING A VISCOSITY OF ABOUT 5 TO 150 CENTIPOISES AT 20*C. COMPRISING: (I) A PHOTOPOLYMERIZABLE COMPONENT COMPRISING (A) AN UNSATURATED POLYESTER HAVING A FUSING POINT ABOVE 100*C. CONTAINING IN THE MOLECULE AT LEAST ONE SEGMENT (A) SELECTED FROM THE GROUP CONSISTING OF THE SEGMENT (1) OF THE FORMULA:   -((CH2)Y-OOC-R2-COO)Z-(CH2)Y-   WHEREIN R1 REPRESENTS AN ALKYLENE GROUP HAVING 2 TO 4 CARBON ATOMS; X IS 2 TO 100) AND THE SEGMENT (2) OF THE FORMULA:   -(1,4-PHENYLENE)-, -(4,4&#39;&#39;-BIPHENYLENE)-,   (-R1-O-)X -((CH2)Y-OOC-R2-COO)Z-(CH2)Y(WHEREIN R2 REPRESENTS A MEMBER SELECTED FROM THE GROUP CONSISTING OF -(1,4-PHENYLENE)-, -(4,4&#39;&#39;-BIPHENYLENE)-, -(1,4-PHENYLENE)-(CH2)W-(1,4-PHENYLENE)AND NAPHTHYLENE GROUP; Y IS 2 TO 4; Z IS 1 TO 10; AND W IS 1 TO 4) AND THE SEGMENT (B) CORRESPONDING TO THE RESIDUE OF AN UNSATURATED DICARBOXYLIC ACID; (B) ABOUT 10 TO 150 PARTS BY WEIGHT, BASED UPON 100 PARTS BY WEIGHT OF SAID UNSATURATED POLYESTER (A), OF AT LEAST ONE ETHYLENICALLY UNSATURATED MONOMER, DIFFERENT FROM THE UNSATURATED POLYESTER POLYMER (A); AND (C) ABOUT 0.01 TO 5 PARTS BY WEIGHT, BASED UPON 100 PARTS BY WEIGHT OF SAID UNSATURATED POLYESTER, OF A PHOTOPOLYMERIZATION INITIATOR; (II) AT LEAST ONE SOLVENT SELECTED FROM THE GROUP CONSISTING OF CHLORINATED ALIPHATIC HYDROCARBONS, BROMINATED ALIPHATIC HYDROCARBONS, KETONES, CYCLIC ETHERS AND PYRIDINE, SAID SOLVENT HAVING A RELATIVE DRYING VELOCITY OF 500 TO 10,000. THIS PHOTOSENSITIZING SOLUTION IS COATED IN A THICKNESS BETWEEN 10 TO 200U ON A SUPPORT AND EXPOSED TO ACTINIC LIGHT THROUGH AN IMAGE TRANSPARENCY. THEN, THE NON-EXPOSED AREA IS REMOVED AND THE SURFACE IS TREATED WITH A DENSENSITIZING AGENT TO GIVE A RELIEF LITHOGRAPHIC PLATE.

United States Patent 3,677,755 RELIEF LITHOGRAPHIC PLATES ANDPHOTOSENSITIZING SOLUTIONS Hisaaki Fukui and Taketoshi Araki, Tokyo, andYoshikane Fuchi, Iruma-gun, Japan, assignors to Asahi Kasei KogyoKabushiki Kaisha, Osaka, Japan No Drawing. Filed Aug. 28, 1969, Ser. No.853,948 The portion of the term of the patent subsequent to Feb. 22,1989, has been disclaimed Int. Cl. G03c /00 US. Cl. 96-351 13 ClaimsABSTRACT OF THE DISCLOSURE A photosensitizing solution having aviscosity of about 5 to 150 centipoises at 20 C. comprising:

(1) a photopolymerizable component comprising (A) an unsaturatedpolyester having a fusing point above 100 C. containing in the moleculeat least one segment (a) selected from the group consisting of thesegment (1) of the formula:

(wherein R represents an alkylene group having 2 to 4 carbon atoms; x is2 to 100) and the segment (2) of the formula:

F l E(CH2)y O-RZ-'JJ OJI (wherein R represents a member selected fromthe group consisting of and naphthylene group; y is 2 to 4; z is 1 toand w is 1 to 4) and the segment (b) corresponding to the residue of anunsaturated dicarboxylic acid;

(B) about 10 to 150 parts by weight, based upon 100 parts by weight ofsaid unsaturated polyester (A), of at least one ethylenicallyunsaturated monomer, different from the unsaturated polyester polymer(A); and

(C) about 0.01 to 5 parts by weight, based upon 100 parts by weight ofsaid unsaturated polyester, of a photopolymerization initiator;

(II) at least one solvent selected from the group consisting ofchlorinated aliphatic hydrocarbons, brominated aliphatic hydrocarbons,ketones, cyclic ethers and pyridine, said solvent having a relativedrying velocity of 500 to 10,000.

This photosensitizing solution is coated in a thickness between 10 to200 i on a support and exposed to actinic light through an imagetransparency. Then, the non-exposed area is removed and the surface istreated with a desensitizing agent to give a relief lithographic plate.

This invention relates to relief lithographic plates. It moreparticularly refers to novel photosensitizing solutions which are usefulfor preparing relief lithographic plates. 7

Heretofore, there were two types of lithographic plates. One includeslithographic plates having a relief of 5 to 10 in thickness preparedfrom an albumen sensitizer and the other includes presensitized platesand wipe-on plates which are further classified into azo resin or azidoresin sensitizing solutions and photopolymer-type sensitizing solutionsmainly comprising a photopolymerizable 3,677,755 Patented July 1972component. However, the adhesive strength and abrasion of the image areaaccording to said lithographic plates and the plates from said azo resinor azido resin sensitizing solutions are low and at most 50,000 to60,000 copies may be produced from a single plate. Further, as thethickness of the image area of such plates are in the range of 5 to 10after etching or development, the clearness and accuracy of prints areremarkably lost. Therefore deep-etch planoplates which substantiallyavoid such disadvantages have an advantage over these plates in spite ofthe complicated process for preparing such. As presensitized plates,Riston (trademark by E. I. du Pont de Nemours & Co.) and Kontrol Plate(trademark by Ball Brothers Co.) produced from a photopolymertypephotopolymerizable component are on sale. However, the thickness ofphotopolymerizable layer of these presensitized plates are the same asthat of the conventional ones from a diazo resin sensitizing solution.

It is an object of this invention to provide a novel photosensitizingsolution which is particularly useful in the production of relieflithographic plates.

Another object of this invention is to provide a novel relieflithographic plate which substantially avoids the difiiculties of priorart relief lithographic plates.

Other and additional objects of this invention will become apparent froma consideration of this entire specification and the claims.

In accord with and fulfilling these objects, one aspect of thisinvention resides in a photosensitizing solution compnsmg:

(I) a photopolymerizable component containing (A) an unsaturatedpolyester having a fusing point above C. comprising a polycondensationreaction product of at least one member (a) selected from the groupconsisting of compounds (1) of the formula:

HOR -0 1 (wherein R represents alkylene group having 2 to 4 carbonatoms; x is 2 to 100) and compounds (2) of the formula:

and naphthylene group; is 2 to 4; z is 1 to 10; and w is 1 to 4) and (b)an ethylenically unsaturated dicarboxylic acid;

(B) About 10 to parts by weight, based upon 100 parts by weight of saidunsaturated polyester (A), of at least one ethylenically unsaturatedmonomer, different from the unsaturated polyester polymer (A); and

(C) About 0.01 to 5 parts by weight, based upon 100 parts by weight ofsaid unsaturated polyester, of a photopolymerization initiator;

(II) At least one solvent selected from the group consisting ofchlorinated aliphatic hydrocarbons, brominated aliphatic hydrocarbons,ketones, cyclic ethers and pyridine, said solvent having a relativedrying velocity of 500 to 10,000.

Another aspect of this invention resides in the photopolymerized productof the photopolymerizable layer described herein. This photopolymerizedproductv is excellent for relief lithographic plates.

Still another aspect of this invention lies in the production of arelief lithographic plate by forming a photopolymerizable layer bycoating a support with the photosensitizing solution in a thicknessbetween to 200 exposing a selected area of said layer to actinic lightuntil photopolymerization of the exposed area of said layer issubstantially completed, removing the nonexposed area and subsequentlytreating the surface of the resulting layer with a desensitizing agent.

By using such photosensitizing solutions which are of the solvent-drying01f type, mainly comprising an unsaturated polyester,photopolyrnerizable layers of any desired thickness from 10 to 200 witha high accuracy of thickness may be formed. In the preparation of arelief lithographic plate these photosensitizing solutions are notaffected by temperature and moisture, and the time for exposure toactinic light may be maintained constant in any atmospheres. Only theconventional treatment with a desensitizing agent after development ofthe polymer is necessary and the steps of lacquer-coating and etchingneed not be used. Thus, the steps in the preparation of lithographicplates are reduced and the working efficiency is appreciably improved.

The relief lithographic plates according to the present invention arenovel printing plates and may be said to have the intermediatecharacteristics between those of lithographic plates and plates fordry-offset printing. In printing with these plates a conventional offsetprinting machine is employed. Although the image area is relieftype, ahigh-speed printing of over 10,000 copies per hour is possible. When thethickness of the image area is in the range of 150 to 200 1. adry-offset printing may be employed.

An unsaturated polyester in the photopolymerizable component is producedby the conventional condensation reaction of an etherdiol correspondingto the abovedescribed compound (1) and having the formula:

(wherein R represents alkylene group having 2 to 4 carbon atoms; x is 2to 100) and/or an esterdio corresponding to the above-described compound(2) and having the formula:

(wherein R represents a member selected from the group consisting of andnaphthylene group; y is 2 to 4, z represents 1 to 10; w is 1 to 4) withan unsaturated dicarboxylic acid or the derivative thereof.

Exemplary etherdiols include polyethyleneglycols having 2 to 100 of CHCH O group in the main chain, polypropyleneglycols having 2 to 100 ofgroup or -CH CH CH O- group in the main chain, polybutyleneglycolshaving 2 to 50 of group in the main chain and copoly (oxyethylene-oxy:propylene)glycols having 2 to 50 of CH CH O-- 4 group and --CH CH(CH)O-- group respectively in the main chain.

The esterdiols may be easily and readily produced by the condensationreaction of a polymethyleneglycol having the formula:

HO-(CHzh-OH (wherein y is 2 to 4) with an aromatic dicarboxylic acid orthe methyl or ethylester thereof having a formula:

(wherein R represents a member selected from the group consisting of andnaphthylene group; R represents a member selected from the groupconsisting of hydrogen atom, methyl and ethyl group; w is 1 to 4).

Such esterdiols are produced by (A) reacting the above-describedpolymethyleneglycol with, for example, the above-described aromaticdicarboxylic acid dimethylester in an inert gas atmosphere at atemperature between and 300 C. in such amounts as to provide anesterdiol having a desired degree of polymerization or a desiredmolecular weight with the produced methanol being distilled off or by(B) adding a or more times moles of a polymethyleneglycol to, forexample, an aromatic dicarboxylic acid dimethylester in an inert gasatmosphere at a temperature between 150 and 200 C. with the producedmethanol being distilled oif and raising the temperature of theresulting reaction mixture to between 200 and 300 C. and, if necessary,with the produced polymethyleneglycol being distilled 05 under reducedpressure to provide an esterdiol having a desired degree ofpolymerization or a desired molecular weight.

The polymethyleneglycols include, for example, ethyleneglycol,1,3-propanediol and 1,4butanediol.

Exemplary aromatic dicarboxylic acids or methyl or ethylesters thereofutilized for the preparation of abovedescribed esterdiols includeterephthalic acid, -p,p'-biphenyldicarboxylic acid,bis-(p-carboxyphenyl)-methane, 1,2-bis-(p-carboxyphenyl)-ethane, 1,3-bis- (p-carboxyphenyl) -propane, l,4-bis-(p-carboxyphenyl)-butane,1,5-naphthalene-dicarboxylic acid, 1,Z-naphthalenedicarboxylic acid,2,S-naphthalene-dicarboxylic acid, 2,7-naphthalene-dicarboxylic acid,and dirnethyl and diethylesters thereof.

Exemplary unsaturated dicarboxylic acids and derivatives thereofutilized for the preparation of the first component i.e. an unsaturatedpolyester include maleic acid, fumaric acid, citraconic acid, methaconicacid, itaconic acid, glutaconic acid, muconic acid, aconitic acid, loweralcohol esters thereof, for example, dirnethyl and diethylestersthereof, maleic anhydride, citraconic anhydride.

In order to change hardness or flexibility of the photopolymerizablecomponent after photopolymerization by varying the double bondequivalent (the molecular weight per one double bond) in an unsaturatedpolyester a part of the segment (3) corresponding to an ethylenicallyunsaturated dicarboxylic acid or the derivative thereof may besubstituted with a saturated or aromatic dicarboxylic acid or thederivative thereof. When the amount of such saturated or aromaticdicarboxylic acid or the derivative thereof is more than 90 mole percentof the ethylenically unsaturated dicarboxylic acid or the derivativethereof, the

' chemical resistance and the tensile strength of the photopolymerizablecomponent after photopolymerization becomes unfavourably lower.

Such saturated or aromatic dicarboxylic acids (nonethylenicallyunsaturated) and the derivatives thereof include, for example, malonicacid, methylmalonic acid, succinic acid, methylsuccinic acid, glutaricacid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acidand the lower alcohol esters thereof such as dimethylester anddiethylester.

The unsaturated polyesters containing segments derived from thecompounds (1) and/or (2) and the acid (b) of this invention are producedby reacting said etherdiol or said esterdiolor :the mixture thereof withsaid ethylenically unsaturated dicarboxylic acid or a derivative thereofand, if necessary, asaturated dicarboxylic acid or a derivative thereofas aforesaid, in an inert atmosphere at a temperature .of 150 C. to 300C. Thus produced unsaturated polyesters have a fusing point above 100 C.

Exemplary ethylenically unsaturated monomers (b) include acrylamidessuch as acrylamide,

methacrylamide, N-hydroxymethylacrylamide,N-hydroxymethylmethacrylamide, N -methoxymethylacrylamide,N-methoxymethylmethacrylamide, N-ethoxymethylacrylamide,N-ethoxymethylmethacrylamide, N-butoxymethylacrylamide,N-butoxymethylmethacrylamide, N,N'-methylenebisacrylamide,N,N'-methylenebismethacrylamide, N,N'-hexamethylenebisacrylamide,N,N-hexamethylenebismethacrylamide,

acrylic acid and acrylates such as propylacrylate, butyl acrylate,Z-hydroxyethyl acrylate, Z-hydroxypropyl acrylate, ethyleneglycoldiacrylate, propyleneglycol diacrylate, diethyleneglycol diacrylate,triethyleneglycol diacryate, polyethyleneglycol diacrylate (an averagemolecular weight of the polyethyleneglycol being below about 2000)polypropyleneglycol diacrylate (an average molecular Weight of thepolypropyleneglycol being below about 2000), 1,4-butyleneglycoldiacrylate, glycerin triacrylate, trimethylol propane triacrylate, allylacrylate, glycidyl acrylate, cyclohexyl acrylate, tetrahydrofurfurylacrylate, methacrylic acid or methacrylates such as propyl methacrylate,butyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropylmethacrylate, ethyleneglycol dimethacrylate, propyleneglycoldimethacrylate, diethyleneglycol dimethacrylate, triethyleneglycoldimethacrylate, polyethyleneglycol dimethacrylate (an average molecularweight of the polyethylene glycol being below about 2000), polypropyleneglycol dimethacrylate (an average molecular weight of thepolypropyleneglycol being below about 2000), 1,4-butyleneglycoldimethacrylate, glycerin trimethacrylate, trimethylolpropanetrimethacrylate, allylmethacrylate, glycidyl methacrylate, cyclohexylmethacrylate, tetrahydrofurfuryl methacrylate; alpha-substituted acrylicacid such as alpha-chloroacrylic acid, alpha-bromoacrylic acid, styreneand derivatives thereof such as p-vinylphenol, p-vinylbenzoic acid,divinylbenzene; vinyl esters such as vinylstearate, vinyl benzoate;allylesters such as allylmethacrylate, diallyl phthalate; N-vinylphthalimide and N-vinyl succim'mide.

It is preferred to employ such an ethylenically unsaturated monomer inamounts of from about to 150 parts by weight based upon 100 parts byweight of the unsaturated polyester. When the amount of said unsaturatedmonomer is below 10 parts by weight, the rate of the photo crosslinkingreaction is very slow and a mechanical strength after photocrosslinkingis small for the practical use. When said amount is above 1150 parts byweight, 'a flexibility after photocrosslinkingis impaired and achemicalresistance is lowered.

Examples of suitable photopolymerisation initiators include benzoinssuch as benzoin, alphamethylbenzoin, benzoin methyl ether, benzoinethylether, alpha-phenylbenzoin, alpha-allylbenzoin; phenones such asacetophenone, benzophenone, omega-bromoacetophenone disulphides such asdiphenyl disulphide, tetraethylthiuram disulphide, diketones such asbenzyl, di-acetyl; 2-naphthalene sulfonyl chloride.

These photopolymerization initiators are preferably used in an amount ofabout 0.01 .to 5 parts by weight based upon parts by weight of theunsaturated polyester. When the amount of the photopolymerizationinitiator is less than 0.01 part by weight, the photopolymerizationreaction is greatly retarded and is too slow for practical commercialpurposes. On the other .hand, amounts of initiator of more than 5 partsby weight donotsignificantly increase the reaction rate and would beuneconomical.

Known thermal polymerization inhibitors may be employed for the purposeof maintaining storage stability (shelf life) of the photosensitizingsolutions. Such stabilizers may be added when the components of aphotosensitizing solution are admixed or may be added to each componentseparately prior to admixing of the components.

Exemplary thermal polymerization inhibitors include hydroquinone,mono-tert-butyl hydroquinone, phenothiazine, p-diaminobenzene,'beta-naphthol, alpha-naphthol, naphthylamine, pyrogallol, cuprouschloride and nitrobenzene. These inhibitors are added only forcompletely preventing polymerization reaction without the actinicradiation set forth above without restraining the .photopolymerizationreaction. Consequently .the amount of the stabilizers may preferably beabout 0.01 to 2 parts by weight based upon 100 parts by weight of theunsaturated polyester.

Furthermore, a variety of compounds such :as fillers and plasticizersmay be incorporated with the photopolymerizable compositions. Thesecompounds, include, for example, polymethylmethacrylates, polystyrenes,polyurethanes, polyvinylchlorides, poly(styrene-butadiene) polymers,polybutadienes, natural rubbers, pol-yvinylbutyrals,polyvinylpyrrolidone, soluble polyamides, polyvinylacetates, alkydresins, saturated polyesters, cellulose acetates, glass fibers, glasscloths, fine powdery silicon oxides, fine powdery calcium carbonate andmica.

The photosensitizing solution of this invention are readilyphotopolymerized by actinic radiation having Wave lengths below 7,000angstroms, generally between 2,000 and 5,000 angstroms. Practicalsources of such actinic radiation include carbon arc lamps, highpressure mercury lamps, low pressure mercury lamps, UV fluorescent lampsand xenon lamps.

The photosensitizing solutions according to the present invention areobtained by dissolving the photopolymerizable component in'a solvent.Such a solvent is required to have a relative drying velocity V of 500to 10,000, preferably l,000 to 5,000, expressed by the formula:

wherein P represents a vapor pressure (mm. Hg) of the solvent at 20 C.and M represents a molecular weight of the solvent. As for a solventmixture, the relative drying velocity is expressed by the followingformula:

wherein P and M are the same as defined above and m, represents molefraction of i kinds of solvents. With relative drying velocities below500, a layer of photopolymerizable component after coating is lacking inthe accuracy of thickness and a radiate unevenness is observed on thesurface of the layer. On the other hand when the relative 7 dryingvelocity is above 10,000, it is difiicult to control the thickness oflayer and the image area is not clear.

The solvents according to the present invention include, chlorinatedaliphatic hydrocarbons such as dichlorometh- 8 ness of the layer of thephotopolymerizable component while the time is almost constant with theconventional photosensitizing solution. After removal of the negativefilm, the non-image areas are washed out with a 0.01 to See footnotes atend of table.

ate (average molecular weight: 1,055)

ane, chloroform, tetrachloromethane, 1,2-dichloroethane, 2% by weightaqueous solution of sodium hydroxide, potrichloroethylene,tetrachloroethylene, brominated aliphatassium hydroxide, sodiumcarbonate or calcium hydroxtic hydrocarbons such as dibromoethane,isobutyl broide. A processor with a spray nozzle 01' a brush isprefermide, isoamyl bromide; ketones such as acetone, methylable buthand washing and a pouring type washing are ethyl ketone, diacetonealcohol; cyclic ethers such as dioxalso possible. The surface of theplate is then treated with ane, tetrahydrofuran, dioxolan,tetrahydropyrane; and 10 a desensitizing agent. Such desensitizingagents include, pyridine. It is preferred to employ a solvent mixed of afor example, hydrophilic colloids of gum arabic such as cyclic ether anda ketone or a mixture solvent of a chlori- AGUM O and AGUM-Z (trademarksby Hannsegnated aliphatic hydrocarbon and a ketone. In order to gen,Hanover) on sale or C.M.C., phosphoric acid, nitric improve the surfaceconditions of a photosensitizing soluacid and calcium or ammonium saltsthereof, organic tion after coating and to control the relative dryingvelocacids and sodium, potassium or calcium salts thereof. The ity of aphotosensitizing solution, there may preferably sensitizing agent isusually coated with a soft sponge by be employed a lower aliphaticalcohol having 1 to 4 carbon hand. atoms such as methanol, ethanol,isopropanol and normal Thus obtained relief lithographic plates exhibita rebutanol together with the above-described solvent. The markablyimproved printing abrasion compared with the weight ratio of thephotopolymerizable component to the conventional presensitized plates ordeep-etch planoplates solvent is preferably in the range of 1:5 to 1:25.When and over 300,000 prints can be produced from a single the ratio isless than 1:5, 3. part of the photosensitizing plate. Using these relieflithographic plates, a printing solution is precipitated and the storagestability becomes speed is increased and neither abrasion of the platesnor poor. On the other hand, ratios of more than 1:25 decreasepeeling-off of the image area is observed with a high-speed thethickness of coated layer and make it diflicult to conoifset printingmachine. Further, as the image area of the trol the thickness of layer.plates according to the present invention are relief-type,

The photosensitizing solutions according to this inventhe slur ofprinting ink is remarkably reduced due to a tion preferably have aviscosity of about 5 to 150 centismall amount of damping-water.Consequently, clear and poises. accurate prints are obtained. Also it ispossible to print Examples of suitable supports include paper such asembossed paper or foamed material with the relief lithoresin and claysized paper, resin coated paper, metals or graphic plates of thisinvention. alloys such as aluminum, zinc, copper, magnesium, alumi- Thisinvention will be illustrated by the following exnum plated with copper,iron plated with copper, copper amples which are in no way limiting uponthe scope hereplated with chromium, stainless steel or bronze, plasticsof. Parts are by mole unless expressly stated to the consuch aspolyesters, polyamides, polyvinylchlorides, polytrary.methylmethacrylates or polystyrenes and cellulose esters. EXAMPLES :1 TO14 The thickness of these supports are preferably in the range of 0.1 to2.0 mm. Especially aluminum plates of 0.3 to 0.5 T0 100 of theunsaturated Polyester Produced from i thi k d i l t f ()3 t 1,0 i thediol component and the dicarboxylic acid component thi k are f d, setforth in Table 1 there were added 15 g. of ethylene- Thephotosensitizing solutions are especially effective dimethacfylaie, 25of mflhacl'ylflmide, 8- 0f for the production of relief lithographicplates. naphthalene sulfonyl Chloride and gof p y' F l i preparing aelief lithgg aphic l a amine and 100 g. of the resulting mixture weredissolved support to be utilized for offset printing such as aluminum in2,000 of 1,2-dich10T0ethahePYI idihe in a 322 111016 plates of 0.3 to0.5 mm. in thickness and zinc plates of 0.3 ratio (referred t0 asSolution) and in 1,800 of to 1 mm i h urfa is usually grained at about00 tetrahydrofuran-ethanol in a 1:1 mole ratio (referred to to 800 mesh,is coated with the photosensitizing solution by Solution), fesphctively-A aluminum P1915 of hand or by a whirler for printing plates at arotating rate in fhicklless, grained at 0 mesh, Was C at d of about 30to 300 r.p.m., a roll coater at a rotating rate Wlth 591131011 and BsohlfiPlla respectively, y a Whirlel' of about 5 to r.p.m. or a flowcoater with an edge 50 for Prlhtmg P at a rotating fate 0f 60 -P- to Pclearance of about 0.1 to 1.0 mm. at a feeding volume 11106 aPhotosellsltilihg p The Plate Was Placed in a of about 20 to 5,000 cc./min. at a rate of the conveyor of (361111131 frame exposed to a 5 Carbonam mp about 0.5 to m./min. When the photosensitizing soluat a dlstance 91 for 50 Seconds thmllgh ga e tion is used for preparation of relieflithographic plates for film of h P inch and developed With a 05% aconvenient ofl'set printing, the surface of support is not 55 aqueousSmhmn hYdI'OXide Solution and Coated with a necessarily grained. Afterthe solvent is removed by dryrubber sohlhfm (trademark y Hanhseggell,ing, the resulting plate is placed in a vacuum frame and Wlth at6611111086 Spohgfi y hand 10 give a exposed at room temperature to asource irradiating acrelief lithographic p Using each of the resultingtinic radiation through a process negative film. The suitplates, aconventional offset printing was carried out to able time for exposurevaries depending upon the thickgive clear and precise prints.

' TABLE 1 D101 Diearboxylic acid Fusing point of un- Photoi ri'.Etherdiol Esterdiol acid acid p 0.) tig 22 5 1 Polyethyleneglycol(average molecu- Fumarie acid 1 0 A 8 lat weight: 200) B 10 2 do doAdipic acid 104 A a B s 3 1,4-butanediol Maleic acid 115 A 3 B 11 4 dodo Adiplc acid 110 A 6 B 9 5 Ethyleneglycol-dimethyl terephthal-Fumaricacid 184 g i;

TABLE 1Continued Diol Dicarboxylic acid Fusing point of un- Photo-Unsaturated Saturated saturated sensitlz- Vis- Ex. dlcarboxylicdicarboxylic polymer ing solucosity No. Etherdiol Esterdiol acid acid0.) tion (cp.)

fi n do Succinic acid 180 A 16 B 14 7 1,3propaneg1ycol-p,p-bispheny1-Itaconic acid 176 A dicarboxyl methyl (average molecu- B 13 lar Weight:2,286).

8 dn ..do Succinle acid.. 174 A 15 B 13 9 Diethylene glycol1,4-butanediol-dimethyl terephthalate. Fumaric acid 151 g. 11 14 10 do.do do Adipic acid--- 148 A 11 B 13 11 do Ethyleneglycol-naphthalic acidGlutaconic 142 A 12 (average molecular weight: 3,015). acid. B 11 12 dodo do Malonic acid 140 A 13 B 10 13 Polyoxyethyleneglycol (averageEthyleneglycol-dimethyl terephthal- Furnaric acid Adipic acid 145 A 11molecular weight: 600). ate (average molecular weight: B 14 14Polypropyleneglycol (average Ethyleneglyeol-l,3-bis-p-carboxyl ..do "do,139 A 11 molecular weight: 400) phenyl ethane. B

News:

l. Mole ratio of diol to dicarboxylic acid was 1:1. 2. Mole ratio ofetherdiol to ester (1101 was 4:6.

3. Mole ratio of unsaturated dicarboxylic acid to saturated dicarboxylicacid was 1:1.

Preparation of unsaturated polyester in Example 1 Preparation ofesterdiol in Example 5 To 824 g. of dimethyl terephthalate and 789 g. ofethyleneglycol there was added 0.5 g. of zinc acetate and the mixturewas heated at a temperature of 180 C. to 200 C. under a nitrogenatmosphere. 271 g. of the methanol produced were distilled oif and theresulting mixture was further heated at a temperature of 220 C. to 240C. while 453 g. of ethyleneglycol were distilled ofi to givebis-beta-hydroxyethyl terephthalate having a degree of polymerization of3.2.

Preparation of unsaturated polyester in Example 5 To the resultingesterdiol there were added 144 g. of fumaric acid and 3 g. ofp-toluenesulfonic acid and the mixture was heated at 240 C. for 8 hoursunder a nitrogen atmosphere while the water was distilled off to give anunsaturated polyester having an acid value of 16.5 and a fusing point of184 C.

In Examples 6 to 8 the unsaturated polyesters were prepared in the samemanner as in Example 5.

Preparation of esterdiol in Example 13 To 789 g. of ethyleneglycol therewere added 824 g. of dimethyl terephthalate and 0.5 g. of zinc acetateand the mixture was heated at a temperature of 180 C. to 200 C. for 80minutes under a nitrogen atmosphere while 271 g. of the methanol weredistilled oif. The reaction temperature was gradually increased to a.

temperature of 220 C. to 240 C. and the resulting mixture was furtherreacted for 2.5 hours while 456 g. of ethyleneglycol were distilled off.

Preparation of unsaturated polyester in Example 13 To the resultingesterdiol there were added 155 g. of fumaric acid, 105.5 g. of adipicacid and 3 g. of p-toluenesulfonic acid while the temperature wasmaintained at 240 C. After 30 minutes 523 g. of polyethyleneglycolhaving an average molecular weight of 600 were added to the mixture andthe resulting mixture was reacted at 240 C. for 8 hours under a nitrogenatmosphere while the water produced was distilled off to give anunsaturated polyester having an acid value of 21.4 and a fusing point of145 C.

In Examples 9 to 12 and 14, the unsaturated polyesters were prepared inthe same manner as in Example 13.

EXAMPLE 15 TO 29 To 100 g. of the unsaturated polyester having a fusingpoint of 142 C. produced by the conventional condensation reaction of0.5 part of dipropyleneglycol, 0.5 part ofbis-beta-hydroxyethylmethylene-bisphenyl-dicarboxyl obtained by theester-exchange reaction of ethyleneglycol and dimethyl ester ofp,p'-diphenylrnethane dicarboxylic acid, 0.5 part of fumaric acid and0.5 part of adipic acid, there were added 25 g. ofN-methylol-acrylamide, 25 g. of acrylic acid, 1.0 g. of allylbenzoin and0.02 g. of hydroquinone and 100 g. of the resulting mixture weredissolved in a variety of the solvents shown in Table 2 to give aphotosensitizing solution. An aluminum plate of 0.5 mm. in thickness,grained at 800 mesh, was coated with the photosensitizing solution by aroll coater at a rotating rate of 15 r.p.m. and dried to produce aphotosensitizing plate. The plate was placed in a vacuum frame andexposed to a 500 w. high pressure mercury lamp at a distance of cm. for70 seconds through a negative film of the test chart having charactersof 7 to 34 points and developed with a 0.6% aqueous sodium hydroxidesolution, dried and coated with rubber with a cellulose sponge by handto give a relief lithographic plate for offset printing.

TABLE 2 Weight ratio of photopoiym- Relative Mole erizable duringThickness Example ratio of component to velocity Viscosity of layerResult of number Solvent solvents solvent (V r) (011.) (p) printing 1 15Chloroform 1:10 19, 280 125 68 Bed. 16 Dichloroethane 1:10 26, 780 11571 Bad.

Dibrornoethylene 1:20 1, 690 10 -ood 18 Methylethyl ketone 1: 20 5, 620S 14 Do. 19. 'Diacetone alcohol- 1: 1, 280 10 12 Do. 20. Dioxane 1:15 2,380 24 22 Do. 21. Dioxolan. 1:15 5, 180 22 26 Do. 22 Pyridine- 1:15 1,220 25 22 Do. 23. Trichloroethylene acetone 3: 1 1:10 8, 310 95 57 Do.24.-. Isobutyl bromide-1,Z-dichloroethane.. 1: 1 1:15 4, 940 22 24 Do.25 Methylethyl ketone dioxane 1:5 1:15 2, 920 26 25 Do.

6:1 1:15 16, 840 27 27 Bad. 1:1 1:15 10, 830 24 24 Bad. 1:6 1:15 4,80023 23 Good 5:1:1 1:15 3,626 21 23 Do.

1 As the result of printing, the tone reproduction of the negative wasexamined.

EXAMPLES 30 TO 39 One part of polyethyleneglycol having an averagemolecular weight of 600, 0.5 part of fumaric acid and 0.5 part ofterephthalic acid were polycondensed by the conventional method and theresulting unsaturated polyester had a melting point of 125 C. 100 g. ofthe unsaturated polyester, 30 g. of acrylarnide, g. of styrene, 2 g. ofbenzoin methylether and 0.02 g. of beta-naphthol were thoroughly mixedand 100 g. of the mixture were dissolved in 1.500 g. of dioxane-acetonein the specified mole ratio shown in Table 3 to give a photosensitizingsolution. An aluminum plate of 0.3 mm. in thickness, grained at 800mesh, was coated with the photosensitizing solution by a flow coaterwith an edge clearance of 0.5 mm., varying a feeding volume of thephotosensitizing solution and a rate of the aluminum plate. Theresulting photosensitizing plate was placed in a vacuum frame andexposed to 6 kw. carbon arc lamp at a distance of 1 m. for 2 minutesthrough a negative film of 150 lines per inch and developed with a 05%aqueous sodium hydroxide solution, dried and coated with rubber With asponge by hand to give a relief ing. Using each of the resulting platesmore than 300,000

Example No.:

EXAMPLE 100 g. of the unsaturated polyester obtained in Example 40, 15g. of ethyl acrylate, 30 g. of styrene, 2 g. of diphenyl disulfide and0.1 g. of betanaphthol were thoroughly mixed and 100 g. of the mixturewere dissolved in 1,500 g. of 1,2-dichloroethane-dioxane-methanol in a4:4:1 mole ratio to give a photosensitizing solution having a viscosityof 27 cps. and 'a relative drying velocity of 40 lithographic plate foroffset printing. 3,620. An aluminum plate of 0.3 mm. in thickness wasTABLE 3 Dioxane Relative Feeding Rate of Thickness Example acetonevelocity Viscosity volume aluminum of layer number (mole ratio) (Vr(ep.) (cc/min.) (m./min.) (a) EXAMPLES 40 TO 44 To 100 g. of theunsaturated polyester having a melting point of 102 C. produced from 1part of polyethyleneglycol having an average molecular weight of 600,0.5 part of fumaric acid and 0.5 part of adipic acid there were added 25g. of methylenebisacrylamide, 25 g. of itaconic acid, 2 g. of benzoinand 0.01 g. of hydroquinone and 100 g. of the resulting mixture weredissolved in 2,000 g. of trichloroethylenemethylethyl ketone in a 1:2mole ratio to give a photosensitizing solution having a viscosity of 10cps. and a relative drying velocity of 6,280. A zinc plate of 1 mm. inthickness, grained at 600 to 800 mesh, was coated with thephotosensitizing solution by a vertical-type whirler at the specifiedrotating rate set forth in Table 4 to produce a photosensitizing plate.The plate was placed in a vacuum frame and exposed to a 500 w. mercurylamp at a distance of cm. for 2 minutes through a negative of the testchart having characters of 7 to 34 points and developed with a 0.5%aqueous sodium hydroxide solution, dried and coated with rubber with acellulose sponge by hand to give a relief lithographic plate for offsetprintcoated with the photosensitizing solution by a roll coater at arotating rate of 10 r.p.-m. to produce a photosensitizin-g plate havinga layer of 25 1. The plate was placed in a vacuum frame and exposed to a2 kw. carbon arc lamp at a distance of 1 m. for 3 minutes through anegative of 150 lines per inch and developed with a 0.5% aqueous sodiumhydroxide solution, dried and coated with rubber with a cellulose spongeby hand to give a relief lithographic plate for ofiset printing.Embossed paper was printed at a printing rate of 10,000 copies per hourusing the resulting plate.

What is claimed is: 1. A photosensitizing solution having a viscosity ofabout 5 to 150 centipoises at 20 C. comprising:

(A) a photosensitive composition comprising (a) an unsaturatedpolyester, (b) 5 to 150 part by weight, based on parts by weight of saidunsaturated polyester, of at least one additional polymerizableethylenically unsaturated monomer containing at least one CH =C groupand havinga boiling point about 100 C. at normal atmospheric presure and(c) 0.001 to 10 parts by weight, based on 100 parts by weight of saidunsaturated polyester, of a photopolymerization initiator, saidunsaturated polyester being prepared by the interpolymerization,polycondensation reaction of a diol component and an acid component insubstantially stoichiometric amounts, wherein said diol componentcomprises an etherdiol (I) of the formula:

wherein R represents alkylene group having 2 to 4 carbon atoms; x is 2to 100 and 10 to 90 mole percent, based on the total diol content of anesterdiol (II) of the formula:

wherein R represents a member selected from the group consisting of:

and naphthylene group, y is 2 to 4; z is 2 to 10-; and w and u arerespectively 1 to 4; and wherein said acid component comprises anunsaturated dicarboxylic acid, an anhydride thereof or a lower alcoholester thereof, and

(B) at least one solvent selected from the group consisting ofchlorinated aliphatic hydrocarbons, brominated aliphatic hydrocarbons,ketones, cyclic ethers and pyridine, said solvent having a relativedrying velocity of 500 to 10,000.

2. A photosensitizing solution as claimed in claim 1, wherein saidsolvent is used together with at least one lower aliphatic alcoholhaving 1 to 4 carbon atoms.

3. A photosensitizing solution as claimed in claim 1, wherein saidphotosensitive composition additionally contains about 0.01 to 2 partsby weight, based upon 100 parts by weight of the unsaturated polyester,of a thermal polymerization inhibitor.

4. A photosensitizing solution as claimed in claim 1, wherein the weightratio of the photosensitive composition to the solvent is in the rangeof 1:5 to 1:25.

5. A photosensitizing solution as claimed in claim 1, wherein thechlorinated aliphatic hydrocarbon is selected from the group consistingof dichloromethane, chloroform, tetrachloromethane, 1,2-dichloroethane,trichloroethylene and tetrachloroethylene.

6. A photosensitizing solution as claimed in claim 1, wherein thebrominated aliphatic hydrocarbon is selected from the group consistingof dibromoethane, isobutyl bromide and isoamyl bromide.

7. A photosensitizing solution as claimed in claim 1, wherein the ketoneis selected from the group consisting of acetone, methylethyl ketone anddiacetone alcohol.

8. A photosensitizing solution as claimed in claim 1, wherein the cyclicether is selected from the group consisting of dioxane, tetrahydrofuran,dioxolan and tetrahydropyrane.

9. Relief lithographic plate comprising a support of HOR O H 1 wherein Rrepresents alkylene group having 2 t0 4 carbon atoms; x is 2 to and acompound (2) of the formula;

J. wherein R represents a member selected from the group consisting ofand naphthylene group; y is 2 to 4; z is 1 to 10; and w is 1 to 4 and anunsaturated dicarboxylic acid (b) having a fusing point above 100 C.;

(B) about 10 to parts by weight, based upon 100 parts of saidunsaturated polyester, of at least one ethylenically unsaturatedmonomer, different from the unsaturated polyester polymer (A); and

((3) about 0.01 to 5 parts by weight, based upon 100 parts by weight ofsaid unsaturated polyester, of a photopolymerization initiator.

10. A relief lithographic plate as claimed in claim 9, wherein thesupport is selected from paper, metal, alloy, plastic and celluloseester.

11. A relief lithographic plate as claimed in claim 10, wherein thesupport is aluminum plate of 0.3 to 0.5 mm. in thickness.

12. A relief lithographic plate as claimed in claim 10, wherein thesupport is zinc plate of 0.3 to 1.0 mm. in thickness.

13. A process for preparing relief lithographic plates which comprisesforming a photopolymerizable layer by coating a support of 0.1 to 2.0mm. in thickness with the photosensitizing solution claimed in claim 1in a thickness between 10 to ZOO 1., exposing a selected area of thephotopolymerizable layer to actinic light until photopolymerization ofthe exposed area of said layer is substantially completed, removing thenon-exposed area of said layer and subsequently treating the surface ofsaid layer with a desensitizing agent.

References Cited UNITED STATES PATENTS (CHEM-OH 3,483,169 12/1969 Caseet al. 260861 3,196,131 7/1965 Mayer et al 26086l 2,855,373 10/1958Guenther 260-861 NORMAN G. TORCHIN, Primary Examiner E. C. KIMLIN,Assistant Examiner US. Cl. X.R. 96-115 UNITE!) STATES PA'FEN'F. ()FWCHCEQIR'Q'FE WLCATE 6F CQRRC'ELEUN Patent No. 3,677,755 Dated y 1972lnvontofls) Hisaaki Fukui et a1 It is certified that error appears inthe above-identified patent and that said Letters Patent are herebycorrected as shown below:

Col. 1 after line 9 The following Foreign Application Priority Data ismissing:

"Japan, No. 64952 of September 11, 1968 and Japan No. 80382 of November5, 1968".

Signed and sealed this 6th day of March 1973.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT (EOTTSCHALK Attesting Officer Commisslonerof Patents ORM O-1050 (10-69) USCOMM-DC 60376-7 69 fir u.s. GOVERNMENTPRIN'HNG orncz: I969 o-asaa34

